The present invention relates to a new and improved construction of a plastic bone serving as a training device or teaching aid for surgeons or other medical personnel for mechanically connecting bone fractures.
For the surgical treatment of bone fractures the reader is directed to the state of the art publication entitled "Manual der Osteosynthese", by M. E. Muller, M. Allgower, H. Willenegger, Springer Publishers, Berlin, Heidelberg, N.Y. 1969. In this text there has been explained, on the basis of numerous illustrations and descriptive material, the technical aids and techniques available to the orthopedic surgeon for treating complicated fractures and shattering of the bones, especially at the extremities, in order to enable the patient to again reuse the injured bone after a relatively short period of time and thereafter to render possible complete healing of the damaged limb. These treatment techniques and especially the mechanical-technical proper use of the available aids i.e. fracture appliances or the like, require the surgeon to participate in intensive training courses in orthopedic surgery to avoid making mistakes in practice, and further, requires practical experience with mechanical connection techniques employed at bones used for training or teaching purposes.
The training bones heretofore available primarily were animal bones procured from slaughter houses, and in rare situations also human bones. The available animal bones, especially with respect to their internal and external structure, but also with regard to their strength, considerably deviated from analogous human bones. Human bones were only used for training purposes with reservation because of ethical reasons. Additionally, oftentimes they only first could be used after undergoing a longer preservation period and pre-treatment, during the course of which their strength, fracture behavior and mechanical working properties frequently disadvantageously changed in relation to the corresponding properties of the living bone.
Plastic bones heretofore were only known as a toy and chewing or gnawing bone for dogs, for demonstrating the external bone shape, or for assembling a demonstration skeleton. In all these cases there was not provided any marrow cavity, and significantly, the internal structure did not have to correspond in any manner to the natural bone structure.
In U.S. Pat. No. 2,472,819 there have been taught, for instance, bone models and entire limb-skeleton models formed of wood, which extensively correspond in their external shape to the actual human bones. They provide a certain training help for the student of anatomy and surgery in order to properly set fractures and to orient the individual bones in the sockets.
Owing to the extreme differences between a solid natural wooden structure and a bone structure having a marrow cavity, bone lacunae and compact outer shell or layer, it is not possible however to use the same tools for the connection of the fractured parts and not the same fracture setting or orthopedic appliances (screws, etc.).